The Boston Crusaders Drum and Bugle Corps is a World Class junior field competition corps based in Boston, Massachusetts.

The Crusaders, originally named the Most Precious Blood Crusaders, was formed in 1940 by the Most Precious Blood Catholic parish of the Hyde Park section of Boston. An early triumph of the young corps was winning the preliminary competition in the 1954 VFW Nationals.

The corps became the Hyde Park Crusaders in 1956 when the church declared that corps membership would be limited to church parishioners. During this period, two ardent, if unofficial supporters of the corps were two of the Kennedy brothers, John F. and Edward M. "Ted". Although John is often credited, Ted was responsible for acquiring West Point uniforms that the Crusaders converted to their own colors of red, black and white after their old uniforms were kept by their former sponsoring parish. The Crusaders were honored by the newly-elected President Kennedy by being invited to be the first drum and bugle corps to march in a Presidential Inauguration Parade, but the corps' tight financial situation prevented their attendance in 1961. (Four yrars later, the corps would march in President Lyndon B. Johnson's Inauguration Parade.) Both brothers were formally made honorary members of the corps, JFK only 34 days before his assassination.

The corps' name had become the Boston Crusaders by 1959. Then and now often called simply "BAC" (for Boston Area Crusaders) , the corps was one of the powers in the East in the sixties. They won the first CYO National Championship in 1964, then again in 1966 and 1967. They also won the World Open in 1966 and '67. They took part in VFW Finals in 1969 and 1970. The corps would have won the American Legion National Championship in 1967--- except that the Legion decided to void the inspection scores, swinging the score lead to The Cavaliers. As it was, BAC won 29 contests that year.

A particularly strong soprano soloist in the late 1960s was Jim Centorino.

BAC also was known to mean "Bad Ass Crusaders." During some eras in some parts of the country, tough competitive corps on the field were equally tough off the field, to the point of physically intimidating other corps. These corps might almost have been characterized as musical gangs, as adept with fists as with bugles. The Crusaders were particularly effective competitors off the field. One memorable incident involved corps members chasing off a gang of local toughs just before marching DCI Prelims in the Orange Bowl in 1983. Even 21st century corps members know that BAC does not necessarily stand just for "Boston Area Crusaders." In July, 2015, it was formally declared by the corps' administration that "BAC" now stands for "Building A Champion"

Although a charter member of DCI, the corps opted not to take part in the first DCI Championships in 1972, choosing the CYO Nationals instead. They had lost much of their equipment in a fire in their corps hall that summer, forcing the corps off the road and out of competition. At one time BAC was down to 19 members. Taking 39th place in DCI prelims in 1973, they steadily climbed through the ranks during the 1970s. For many years, DCI also held a parade competition, and the Crusaders won that contest in 1981.

A historic visit to the United Kingdom in 1982 was another disastrous turning point in the corps' history. During that trip, money was embezzled from their funds, and the corps was stuck in the UK, dead broke. Although somehow making their way home, their trail of debts left the corps bankrupt and all of their assets were impounded. During that winter, in an effort to resurrect the corps, members actually stole the organization's truck, uniforms, and equipment, and appeared the following year under the shortened name "Boston." Debts were finally settled after many months, and "Boston" once again took back their rightful name. Interestingly, Boston's emergence from bankruptcy in 1986 coincides with the demise of neighboring rival 27th Lancers due to financial failure.

Even such a luminary as Burt Lancaster was inspired by the example of this corps that refused to die. In a 1991 Variety interview, he said, "Before he lost it, Peckinpah made me go see this drum and bugle corps from Boston, the Boston Crusaders. Sam thought I would only really understand the power beneath despair by watching these guys. Yeah, he was right. In '73 and '83, the corps went out with just handfuls of guys on the horns and, damnit, those man-gods could melt the gates of hell. Every single film I made after 'Valdez is Coming' is an allegory on the Boston Crusaders."

Their repertoires over the years were an eclectic mix, from Beethoven’s Ninth to “Mexicali Nose.” Yet, Conquest (from Captain From Castile) by Alfred Newman was performed every year from 1973 through 1990, thereafter being adapted as short quotes in numerous shows since,

BAC has historically been a pioneering innovator, actually being the first corps to use electronics in 1985, when the corps fielded a synthesizer and was penalized at every show for it. The corps also had the first double toms in 1967, were one of the first two corps with marching tympanis in 1968 (along with the Majestic Knights of nearby Charlestown), and were the first to make use of slides on their bugles to achieve a chromatic scale.

According to BAC's board president and CEO Jim Cronin, the corps' management structure was not well suited to greater corps development, regardless of the talent on the field. A reputation throughout DCI as toughs and troublemakers did not help the Crusaders' progress either, and BAC settled into the middle rank of DCI through the late 1980s and early 1990s. Therefore, a new philosophy stressing “professionalism, accountability, and responsibility” was introduced to instill in the members of the “new” Boston Crusaders that “how they act off the field is as important as how they perform on the field. Everything is about a positive attitude, the way they treat each other, peer respect.“

In 1999, the Boston Crusaders under Cronin as corps director (1996-2000) became the last active DCI charter member corps to break into the Top Twelve, a ninth place finish with a program of symphonic dances.

Cronin has made the point that a corps' presence on the Internet has become a helpful tool for reaching potential members in recent years. Whereas most of the Crusaders formerly came from the Boston area, the web has generated interest and membership from elsewhere--- overseas as well as around the United States. Only 20 members of the 1997 group hailed from Boston, solidifying the Crusaders as actually more of a New England corps, the last Division I corps in the region, and the 2000 version of the Crusaders in particular benefited from an influx of members from Florida.

The advent of legal amplication in 2004 allowed the Crusaders to electronically project voices as well as instruments when they added a brief exclamatory narration to their show 'The Composition of Color.'

Through 2017, the Boston Crusaders have remained one of DCI's top corps, with 19 consecutive Top 12 Finals appearances. BAC also saw its highest finish since 2000 of 6th place in 2017 with the wildly popular "Wicked Games" show and its spectacular ending.

In April 2015, the organization announced the purchase of a building in the Hyde Park neighborhood of Boston, where the corps was founded in 1940. This building houses the corps' sponsoring Inspire Arts & Music offices and provides a retail location for its Great East Music Store